checkbox.java

gcc的组建

  * Initializes a new instance of <code>Checkbox</code> with the specified
  * label, an initial state of off, and that is not part of any checkbox
  * group.
  *
  * @param label The label for this checkbox.
  */
public
Checkbox(String label)
{
  this(label, false, null);
}

/*************************************************************************/

/**
  * Initializes a new instance of <code>Checkbox</code> with the specified
  * label and initial state, and that is not part of any checkbox
  * group.
  *
  * @param label The label for this checkbox.
  * @param state The initial state of the checkbox, <code>true</code> for
  * on, <code>false</code> for off.
  */
public
Checkbox(String label, boolean state)
{
  this(label, state, null);
}

/*************************************************************************/

/**
  * Initializes a new instance of <code>Checkbox</code> with the specified
  * label, initial state, and checkbox group.
  *
  * @param label The label for this checkbox.
  * @param group The checkbox group for this box, or <code>null</code>
  * if there is no checkbox group.
  * @param state The initial state of the checkbox, <code>true</code> for
  * on, <code>false</code> for off.
  */
public
Checkbox(String label, CheckboxGroup group, boolean state)
{
  this(label, state, group);
}

/*************************************************************************/

/**
  * Initializes a new instance of <code>Checkbox</code> with the specified
  * label, initial state, and checkbox group.
  *
  * @param label The label for this checkbox.
  * @param state The initial state of the checkbox, <code>true</code> for
  * on, <code>false</code> for off.
  * @param group The checkbox group for this box, or <code>null</code>
  * if there is no checkbox group.
  */
public
Checkbox(String label, boolean state, CheckboxGroup group)
{
  this.label = label;
  this.state = state;
  this.group = group;

  if ( state && group != null )
    {
      group.setSelectedCheckbox(this);
    }
}

/*************************************************************************/

/*
 * Instance Variables
 */

/**
  * Returns the label for this checkbox.
  *
  * @return The label for this checkbox.
  */
public String
getLabel()
{
  return(label);
}

/*************************************************************************/

/**
  * Sets the label for this checkbox to the specified value.
  *
  * @param label The new checkbox label.
  */
public synchronized void
setLabel(String label)
{
  this.label = label;
  if (peer != null)
    {
      CheckboxPeer cp = (CheckboxPeer) peer;
      cp.setLabel(label);
    }
}

/*************************************************************************/

/**
  * Returns the state of this checkbox.
  *
  * @return The state of this checkbox, which will be <code>true</code> for
  * on and <code>false</code> for off.
  */
public boolean
getState()
{
  return(state);
}

/*************************************************************************/

/**
  * Sets the state of this checkbox to the specified value.
  *
  * @param state The new state of the checkbox, which will be <code>true</code>
  * for on or <code>false</code> for off.
  */
public synchronized void
setState(boolean state)
{
  this.state = state;
  if (peer != null)
    {
      CheckboxPeer cp = (CheckboxPeer) peer;
      cp.setState (state);
    }
}

/*************************************************************************/

/**
  * Returns an array of length one containing the checkbox label if this
  * checkbox is selected.  Otherwise <code>null</code> is returned.
  *
  * @return The selection state of this checkbox.
  */
public Object[]
getSelectedObjects()
{
  if (state == false)
    return(null);

  Object[] objs = new Object[1];
  objs[0] = label;

  return(objs);
}

/*************************************************************************/

/**
  * Returns the checkbox group this object is a member of, if any.
  *
  * @return This object's checkbox group, of <code>null</code> if it is
  * not a member of any group.
  */
public CheckboxGroup
getCheckboxGroup()
{
  return(group);
}

/*************************************************************************/

/**
  * Sets this object's checkbox group to the specified group.
  *
  * @param group The new checkbox group, or <code>null</code> to make this
  * object part of no checkbox group.
  */
public synchronized void
setCheckboxGroup(CheckboxGroup group)
{
  this.group = group;
  if (peer != null)
    {
      CheckboxPeer cp = (CheckboxPeer) peer;
      cp.setCheckboxGroup (group);
    }
}

/*************************************************************************/

/**
  * Creates this object's native peer.
  */
public void
addNotify()
{
  if (peer == null)
    peer = getToolkit ().createCheckbox (this);
  super.addNotify ();
}

  public ItemListener[] getItemListeners ()
  {
    return (ItemListener[])
      AWTEventMulticaster.getListeners (item_listeners, ItemListener.class);
  }

/**
  * Adds a new listeners to the list of registered listeners for this object.
  *
  * @param listener The new listener to add.
  */
public synchronized void
addItemListener(ItemListener listener)
{
  item_listeners = AWTEventMulticaster.add(item_listeners, listener);
}

/*************************************************************************/

/**
  * Removes a listener from the list of registered listeners for this object.
  *
  * @param listener The listener to remove.
  */
public synchronized void
removeItemListener(ItemListener listener)
{
  item_listeners = AWTEventMulticaster.remove(item_listeners, listener);
}

/*************************************************************************/

/**
  * Processes this event by calling <code>processItemEvent()</code> if it
  * is any instance of <code>ItemEvent</code>.  Otherwise it is passed to
  * the superclass for processing.
  *
  * @param event The event to process.
  */
protected void
processEvent(AWTEvent event)
{
  if (event instanceof ItemEvent)
    processItemEvent((ItemEvent)event);
  else
    super.processEvent(event);
}

/*************************************************************************/

/**
  * Processes this event by dispatching it to any registered listeners.
  *
  * @param event The <code>ItemEvent</code> to process.
  */
protected void
processItemEvent(ItemEvent event)
{
  if (item_listeners != null)
    item_listeners.itemStateChanged(event);
}

void
dispatchEventImpl(AWTEvent e)
{
  if (e.id <= ItemEvent.ITEM_LAST
      && e.id >= ItemEvent.ITEM_FIRST
      && (item_listeners != null 
	  || (eventMask & AWTEvent.ITEM_EVENT_MASK) != 0))
    processEvent(e);
  else
    super.dispatchEventImpl(e);
}

/*************************************************************************/

/**
  * Returns a debugging string for this object.
  */
protected String
paramString()
{
  // Note: We cannot add the checkbox group information here because this
  // would trigger infinite recursion when CheckboxGroup.toString() is
  // called and the box is in its selected state.
  return ("label=" + label + ",state=" + state + "," + super.paramString());
}

/**
 * Gets the AccessibleContext associated with this <code>Checkbox</code>.
 * The context is created, if necessary.
 *
 * @return the associated context
 */
public AccessibleContext getAccessibleContext()
{
  /* Create the context if this is the first request */
  if (accessibleContext == null)
  {
    AccessibleAWTCheckbox ac = new AccessibleAWTCheckbox();
    accessibleContext = ac;
    addItemListener(ac);
  }
  return accessibleContext;
}

  /**
   * Generate a unique name for this checkbox.
   *
   * @return A unique name for this checkbox.
   */
  String generateName()
  {
    return "checkbox" + getUniqueLong();
  }

  private static synchronized long getUniqueLong()
  {
    return next_checkbox_number++;
  }
}